WASHINGTON — Satellite and rocket hardware provider Ruag Space signed a contract with Firefly Aerospace to provide payload adapters for its small launch vehicles.

Ruag Space will provide the adapters, which lock satellites in place during launch and release them once in space, as part of a long-term purchase agreement.

Ruag Space spokesperson Carrie Rice said the purchase agreement starts with an order for six launches, but is structured as a multi-year deal without set quantities.

Austin, Texas-based Firefly is building a rocket called Firefly Alpha intended to launch 630 kilograms to a 500-kilometer sun-synchronous orbit. The vehicle’s first flight is scheduled for December, according to the company website.

Rice said Ruag Space builds its payload adapters in Linköping, Sweden. The company has provided adapters for more than a dozen launchers, including Rocket Lab’s Electron and Arianespace’s Vega rockets and larger vehicles such as Khrunichev’s Proton and United Launch Alliance’s Atlas 5 and Delta 4 rockets, she said.

“Our agreement with RUAG provides our customers the highest level of assurance that their spacecraft missions will be successful,” Tom Markusic, CEO of Firefly Aerospace, said in a July 19 statement.

Ruag Space says its hardware has separated more than 600 satellites in space without any failures. The payload adapter Firefly will use, the PAS 937S, has flown on 171 missions, Rice said.